|Abstract: ||聚羥基烷酯（PHA）是由微生物發酵生產出來的塑膠，有別於現在的石化合成塑膠。PHA具有許多之優點，同時符合「清潔生產」與「環保材料」的要求，因此在國內外引起學術界與工業界廣泛研究。不過為大多數細菌所生產的PHA是聚羥基丁酯(PHB)及其共聚合體-聚羥基丁酯羥基戊酯(PHBV)，兩者都是高度結晶性的高分子，結晶度可達50~70%。結晶度是影響高分子性質的重要因素之一，包括機械、物理、熱力和光學性質。因此PHB或PHBV的結晶行為，就值得進一步地深入研究。另外，PHB雖然具有許多優點，但是本身仍有一些缺點，譬如熱穩定性低、硬脆性等，作為材料應用仍有不足之處，而且共聚物韌性的提高也很有限，因此選擇合適的增塑劑或與其他高分子摻合，可以彌補PHB不足。因此利用偏光顯微鏡、X光繞射儀及傅立葉紅外線光譜儀研究PHB及PHBV的結晶行為，包括結晶動力和結晶形態；另外也進一步地研究了 PHB/PEO及PHBV/PEO摻合材料在不同摻合比例下的結晶形態和結晶動力行為。|
Poly(hydroxyalkanoate), PHA, produced from the fermentation of microbial organisms, has many advantages and meets all the requirements of the “environmentally friendly materials” and “green process”. Therefore, it has drawn great interest and studies from the academics and industries. Among them, the most widely produced PHA in the bacteria are poly(hydroxybutyrate), PHB, and its copolymer, poly(hydroxybutyrate-co-hydroxyvalerate), PHBV. Both of them are highly crystalline polymers with 50-70 %. The crystallinity is one of the most important factors that have pronounced effects on the polymer properties including mechanical, physical, thermodynamics and optical properties. Therefore, it is worthy to study on the crystallization behavior of PHB and PHBV from the melt. Though PHB has many beneficial properties as mentioned earlier, yet, it is brittle and thermally unstable. Therefore, it would be beneficial to increase its toughness and processability by the addition of suitable plasticizer or blending with other polymers. Therefore, the following objectives were investigated: the crystallization behavior of PHB and PHBV from the melt, including crystallization kinetics and morphology; the crystallization and phase separation behavior of the polymer blends, PHB/PEO and PHBV/ PEO.